1. Field of the Invention
The present invention relates generally to image scanners, and more specifically to an overhead image scanner and a scanner unit used for the overhead image scanner.
2. Description of the Related Art
A conventional overhead image scanner as shown and described in Japanese Provisional Patent Publication Sho-62-291259 includes a rotary mirror driven by a mechanical cam-and-rod drive system. Rays from a light source are focused by a lens onto the mirror where it is reflected off to a surface to be scanned to form highly illuminated line. Rays reflected from the illuminated line are collected by the mirror and focused by the lens to a linear image sensor. As the mirror is rotated by a small amount, the whole unit is advanced correspondingly so that the illuminated line is successively advanced by a line width and each line-scan output is produced.
However, the prior art scanner requires many mechanical moving parts which tend to wear with time.